At present, bicycle is not just a means of transportation but a tool for exercise, leisure, entertainment, tourism purpose, and it tends to be developed further as fitness equipment. However, traditional upright bicycles cannot meet the above demands.
There are many defects in upright bicycles regarding aerodynamics, human anthropotomy, human biology, hemodynamics and ergonomics: 1. As the rider rides upright on the saddle, the large windward area and air resistance will lower riding efficiency and speed; 2. Upright riding position increases strain on the rider's spine; 3. To eliminate air resistance, the rider has to bend his/her upper body on the handlebar, causing high strain on both abdomen and spin; 4. This position is unfavorable for venous blood backflow of lower limbs; 5. The rider's weight and friction with the saddle make his/her hip uncomfortable and susceptible to other injuries.
To tackle the above disadvantages of traditional upright bicycles, prone bicycles have been proposed, for example, CN1126683C “Bicycle with Chain Drive, Multi-Gear and Pedal Outside the rear wheel”; CN2564461Y “Prone Bicycle”; U.S. Pat. No. 5,887,882A “Prone Bicycle” and U.S. Pat. No. 6,050,584A “Bicycle Placing Rider in Substantially Semi-Prone Riding Position”. In the above proposals, rider's body posture has been changed from upright to prone or semi-prone posture. However, rider's body support problem remains unsolved.
In traditional upright bicycles, the handlebar and the pedal bear most of the rider's upper limb and lower limb weights respectively, while most of rider's body weight falls on the saddle. As explained in a Chinese Patent (No. CN1126683C), the rider's support points include: legs' support on the pedal; thigh and hip's supports on the saddle; chest and shoulder's support on the armpit support (or the shoulder pad and corset's support) and arms and forearm's support on the handlebar. It is not difficult to see that some supports are unreasonable or not effective. First, different from traditional upright bicycles, in prone position, rider's legs are basically horizontal, making them hardly be supported by the pedal. Unless a special-designed pedal is provided (e.g., one with a strap), rider's foot may fall from the pedal; second, in traditional upright bicycles, saddle is the unique and most effective support; however, in prone position, the saddle can hardly supports rider's body that is basically horizontal, in particular, the hip. The saddle, at most, provides limited support to in-leg, a part that is unsuitable either for male or female from the point view of human anatomy; third, also from human anatomy perspective, taking chest as support will affect one's respiratory system; fourth, armpit's support limits rider's control on handlebar direction and makes it inconvenient for on and off a bicycle. In another two patents CN2564461Y and U.S. Pat. No. 5,887,882A, only shoulder support and thoracic and abdominal support are provided, the defects of which have been explained above; at the same time, the technical schemes disclosed in those two patents fail to provide supports for hip and legs on the saddle. That means, there is no support for lower limb. In this case, rider's leg is likely to fall from the pedal. Similarly, U.S. Pat. No. 6,050,584A only provides unreasonable shoulder support and saddle, the defects of which have been explained above. In addition, all the above technical schemes fail to provide fitness function and possibility of postural change, which makes no good for long-distance ride.